FOIA: Radio Transients, Stellar End Products, and SETI Working Group Report

SETI_1.pdf
Radio Transients, Stellar End Products, and SETI Working Group Report
A report on projects to be persued using the Square Kilometer Array (SKA)
Document date: 2002-12-20
Department: Office of Naval Research &National Science Foundation
Author: J. Lazio, D. Backer, J. Cordes, J. Jonas, M. Kramer, M. Rupen and J. Tarter
Document type: NRL Memorandum Report
pages: 15


Archivist's Notes: This is a technical document outlining activities that the SKA should be used for. These include pulsars, transients and some SETI activities.It lays out forefront activities and goes on to explain how the specifications of the SKA will allow these activities to be carried out successfully.

This technical report is for public release and I don't understand why should be under FOIA but I considered as important as the rest of documents we're dealing with. Named as Radio Transients, Stellar End Products, and SETI Working Group Report this report involved performing organizations as Naval Research Laboratory, University of California, Berkley CA, Cornell University, Ithaca NY, Rhodes University, National Radio Astronomy Observatory, SETI Institute and few other universities abroad.

Has been sponsored and monitored by Office of Naval Research and National Science Foundation. The subject terms are: *EXTRATERRESTRIAL RADIO WAVES, *RADIO INTERFEROMETERS, *PULSARS, TRANSIENTS, INTELLIGENCE, SPACE ENVIRONMENTS, ARRAYS, X RAYS, OPTICAL DETECTORS, STARS, SCINTILLATION, RADIO INTERFEROMETRY.. Personally I would define this kind of document as very specific and scientific for most of the readers and great for the science gurus and people who are into this fields.

In short in the document is made clear that the working group has identified the projects mentioned above as forefront science to be pursued with the Square Kilometer Array (SKA) and which drive the specifications of SKA. In particular, pulsars, transients and some Search for Extraterrestrial Intelligence (SETI) activities require observing modes that differ markedly from those designed for imaging modes of sources that do not vary with time. Therefore, care must be taken in the conceptual and design phases of the SKA to ensure that science in this areas can be undertaken and optimized.

This are the main issues that this document deals with.

[edit on 18-2-2008 by Telos]

Since this document is fairly technical for most of the readers, allow me to write some excerpts and make the reading easier and understandable.

Radio Transient Universe The SKA will produce the first, unbiased survey
of the variable radio sky at centimeter wavelengths. A useful comparison is to gamma-ray bursts (GRBs), which were detected only because a previously unexplored region of parameter space for gammaray observations (namely all-sky, high time resolution observations) were conducted. After 30 yr of mystery, GRBs may now prove to be useful probes of the star formation history of the Universe and the intergalactic medium. Based on the known populations of radio transient sources, such a survey could reveal populations of radio pulsars in 1 nearby galaxies (via the emission of giant pulses like those of the Crab pulsars), possibly as distant as the Virgo Cluster. A byproduct of the detection of such pulsars would be direct detection of the ionized local intergalactic medium. In turn, this would allow study of the bulk of the baryons in the local Universe. Such a survey could also reveal microquasars throughout the Local Super-cluster. We emphasize, however, that these predictions are based on the known populations of transient sources. The greatest return from such a survey will (should!) be the detection of currently unknown populations of sources.

Galactic Pulsar Census Radio pulsars provide unparallelled probes of
fundamental physics, and their signals provide unique diagnostics of
intervening media. For example, their pulse periods, particularly those
near 1 ms, constrain the nuclear equation of state; discovery of a pulsar with a pulse period below 1 ms would provide even tighter constraints. Neutron star-neutron star binaries have provided indirect detection of gravitational waves; discovery of neutron star-neutron star binaries in tighter orbits or, particularly, black hole-neutron star binaries would enable more precise tests of strong-field gravity. A timing array of millisecond pulsars could be used to search for gravitational waves with frequencies inaccessible to LIGO and LISA.

SETI Even without detailed knowledge of the luminosity function of ETI
transmitters nor of ETI signal structure, it is almost self-evident that the SKA will allow unprecendented characterization of the ETI sky. Sensitivity of course allows probing to greater distances for a given transmitter strength. For example, the SKA would enable detection of transmitters with radiated powers comparable to that of terrestrial TV stations over parsec-scale distances. Perhaps of far greater importance is the ability to identify and remove terrestrial radio-frequency interference, whose diversity in signal structure may be similar to that of ETI signals. The key traits of the SKA for this purpose are the multiple-beaming capabilities from a station along with an array of stations at widely spaced sites.

SKA Specifications

In this section we discuss SKA specifications, both as they are baselined and
as needed to accomplish the scientific goals described here.



The picture above is the Projection onto the Galactic plane of a simulated SKA survey at 1.4 GHz for pulsars. The blue dots show the number of pulsars detected by the SKA (∼104), assuming 1024 channels across a 400 MHz with a 600 s integration time per pointing. The open circles and black dots show
known pulsars from the Parkes Multibeam survey and Princeton catalog,
respectively. Also shown are the spiral arms as defined in the Cordes-Lazio
electron density model (Cordes & Lazio 2002, in preparation). In the simulation, pulsars are born preferentially in spiral arms but move away from the arms and from the galactic plane according to a velocity distribution
consistent with that of known radio pulsars.





[edit on 2/19/2008 by JacKatMtn]